The present invention relates to a method of and an apparatus for polishing optical elements. In particular, the present invention relates to a machining condition controlling method and apparatus for controlling a machining conditions of swinging motion in a lens polishing apparatus.
Such an apparatus is used for polishing optical elements. A conventional, polishing apparatus for use in a lens polishing machine is shown in FIG. 10. The apparatus comprises a polishing jig 1 for machining a lens 2 and capable of being rotated at a fixed position by a motor (not shown) or the like. A tip portion of a tommy bar 3 is pivotably engaged with a jig 4 for holding the lens 2 so as to depress the lens 2 against the polishing jig 1. The other end of the bar 3 is held movably up and down in a housing 7 which is secured to a tip portion of an arm 7 attached to an end of a connection shaft or rod 5 movably by a screw 6 or the like. The connection rod 5 is held slidably at its center portion by a carrying shaft 8 for performing a swinging motion. The other end of the rod 5 is rotatably engaged to an eccentric pin 9' provided in an eccentric plate 9 with a motor 10.
In such a lens polishing machine with the above construction, when the lens 2 is machined or polished, at first the lens 2 held by the fitting jig 4 is placed on the polishing jig 1, and then the fitting jig 4 is carried on the tommy bar 3. Under these conditions, when the shaft of the polishing jig 1 and the eccentric plate driving motor 10 are rotated, the connection rod 5 is moved right and left while swinging so that the tip portion of the connection rod is subjected to a quasi-circular motion, and thus the lens 2 is slid on the surface of the rotating polishing jig, while effecting the swinging motion, thereby being polished.
In this way, when a number of lenses are successively machined, the worker measures the radius curvature of respective polished lenses, while viewing its radius curvature the attached position to the connection shaft 5 of the arm 7 which carries the tommy bar 3, is changed and the effective length l of the arm 7 is also to thereby obtain the lens 2 having a desired radius curvature.
This operation requires technical skills, so that the operation must be performed by the experts, and thus becomes ineffective.